Vulnerability identifier: #VU54286

Vulnerability risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-33515

CWE-ID: CWE-74

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Dovecot
Server applications / Mail servers

Vendor: Dovecot

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists in the way STARTTLS command in processed by the SMTP server. the commands sent during the session before the STARTTLS command are queued and executed later, after the STARTTLS finished with the client. As a result, a remote attacker can perform a MitM attack and gain access to victim's emails.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Dovecot: 2.3.0 - 2.3.14

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External links
http://dovecot.org/pipermail/dovecot-news/2021-June/000462.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.